FuelInjection
Triumph GT6 MKII custom fuel injection
Problem.
Fuel injection is often regarded by many classic car owners as unnecessarily complicated and not much better than a traditional carburettor – an expensive brand of snake oil! Carburettors are extremely clever bits of kit, they have been refined over decades to perform very well when matched and tuned to a specific engine. To understand fuel injection you must first understand how a carburettor works.
Carburaton is defined as: “the process of mixing air with a fine spray of liquid hydrocarbon fuel” This is exactly the same thing that fuel injection is trying to achieve but in a slightly different way. The carburettor relies on vacuum to draw the fuel out of the jet and atomise it, whereas the fuel injection uses high pressure to atomise the fuel.
Fuel Injection Throttle Bodies.
Jenvey throttle bodies
Jenvey throttle bodies on an Eagle E Types 4.7L engine on our test rig.
TWM throttle bodies
TWM Throttle bodies installed on a CAV GT40 Ford racing engine.
Suzuki throttle bodies
Suzuki GSXR Motorcycle throttle bodies on Geoff's Triumph GT6.
Improvements.
Where a carburettor struggles is when it has to compensate for different conditions – air temperature, coolant temperature, altitude, overrun, cruise, acceleration etc. This is where fuel injection has a major advantage.
Fuel injection uses a number of different sensors to feed information to the electronic control unit (ECU) which then calculates the correct amount of fuel the engine needs under all operating conditions. In the most sophisticated systems sensors can be used to tell the ECU whether the fuel mixture is rich or lean which then allows the ECU to adjust accordingly.
Using these sensors to give the ECU real time data on conditions leads to a huge efficiency gain over a carburettor. In most cases the ECU is also controlling the ignition as well as fuelling. This allows flexibility of ignition timing that is simply not achievable by a traditional distributor.
Burlen SU fuel injection
Advantages.
Advantages of fuel injection:
• Less polluting exhaust emissions
• More precise control of fuelling
• More precise control of ignition timing
• Increased efficiency through better combustion
• Increased power output
• Increased torque output
• Lower fuel consumption
• Ease of tuning
• Addition of other features – driving modes/different power outputs/traction control
GT40 fuel injection
ECU's.
Not all ECU’s are equal – some are better than others. Generally, the more expensive ECU’s have much more refined ways of calculating fuel quantities coupled with the ability to control many more features than you might think even possible!
Out of choice our preferred ECU manufacturer is Life Racing but we have setup many different systems on cars that have come into our workshop.
They include: Emerald – Life – Pectal – Holley – Omex – DTA – Syvecs – F.A.S.T. – Motec – Accel
This gives us a broad depth of knowledge with ECU operating software that can be very useful for troubleshooting problems.
IDA injection
Retro Design.
A common reason for dismissing fuel injection on a classic car is it’s modern appearance. However in recent years several companies have started to address this aesthetic issue. It is now possible to buy throttle bodies that look like Weber DCOE’s carburettors – perfect for an E Type. We have been involved in a project to make SU carburettors with fuel injection hidden in them. In America a company has fitted fuel injectors within a casting that looks like the Weber IDA – perfect for Ford GT40 replicas. This kind of ‘stealth’ engineering is something that we have started to specialise in.
With the increased emphasis being placed on emissions and carbon neutrality, fuel injection on a classic car really starts to make a lot of sense.
Retro designed Fuel Injection throttle bodies.
Burlen Fuel System's HD8 SUi throttle bodies
Burlen Fuel System's HD8 SUi throttle bodies, designed by Taylor Automotive.
Eight Stack IDA Weber lookalike injection
Eight Stack IDA Weber lookalike injection. Great for GT40/Cobra replicas
Jenvey heritage DCOE Throttle bodies
Jenvey heritage DCOE Throttle bodies on an Aston Martin engine. Picture courtesy of Jenvey.
Jaguar 4.2 E-type engine running SUi fuel injection performing a power curve on the dyno. 267HP & 292lbft torque